By the photolysis of the benzene solution of a variety of 2,3-disubstituted (halogeno, methoxy, and acetoxy) 1,4-naphthoquinones, 1, and 1,1-diarylethylenes, 2, 5-aryl-7,12-benz[a]anthracenediones, 3, are obtained in fairly good yields (22–68%).
The divergent preparation of 1,4-naphthoquinones and tetraphene-7,12-diones, which bear the ABCD-ring of landomycins, has been accomplished directly through oxidative reorganization of previously non-isolable cyclobuta[a]naphthalen-4(2H)-ones.